1. Field of the Invention
The invention is related to the field of packet routing, and in particular, to a protocol analyzer that deletes packets or routes packets to other protocol analyzers based on destination addresses.
2. Statement of the Problem
The demand for communication network services is growing dramatically and there is a corresponding growth in the need for communication test systems. A common test system uses protocol analyzers to monitor traffic on communication links in a communication network. The protocol analyzers process the traffic to produce test packets that are transferred to a test computer. The test computer processes the test packets to produce test results for communication network operators. The test computer also transfers test packets to the protocol analyzers to control testing. As the communication network grows, so does the number of protocol analyzers and test packets that are needed to monitor the network traffic.
In some test systems, the protocol analyzers are daisy-chained together. The protocol analyzer at the end of the daisy-chain is connected to a packet network. The packet network is connected to the test computer. The packet network exchanges the test packets between the protocol analyzers and the test computer, but the packet network also transfers other packet traffic that can get into the daisy-chain. In some cases, the test packets only represent a small percentage of the total traffic within the packet network. To avoid processing the other packet traffic, the protocol analyzers only process packets that contain their respective Media Access Control (MAC) address in the destination field.
Increased traffic within the daisy-chain adversely affects the performance of the test system by slowing down communications between the protocol analyzers and the test computer. The traffic increase is due in part to the increased number of protocol analyzers within the daisy-chain, but the traffic increase is also due to the increased amount of other packet traffic within packet network.
To lower the packet traffic within the daisy-chain, the protocol analyzer at the end of the daisy-chain is connected to the packet network through a device, such as a router or hub. The device prevents the other packet traffic from entering the daisy-chain. Unfortunately, the device represents additional cost and complexity that is required for the test system.
To avoid the additional device, routing software or hub circuitry can be added to the protocol analyzer at the end of the daisy-chain. The software router requires additional processing capacity within the protocol analyzer and additional network provisioning by the network operator. The hub circuitry requires additional components and connectors in the protocol analyzer. Unfortunately, the software router or hub circuitry significantly increases the cost and complexity of the protocol analyzer.
The invention solves the above problem with a cost-effective test system that controls the traffic in a daisy-chain of protocol analyzers. The test system screens packets entering the daisy-chain based on the destination addresses in the packets. Advantageously, the system is implemented with simple control processing that does not add significant cost or complexity to the packet network or to the protocol analyzers.
Some examples of the invention include a protocol analyzer that has a control system coupled to a first interface and a second interface. In operation, the first interface receives a packet from a packet network. The control system receives the packet from the first interface and either deletes the packet or transfers the packet to the second interface based on a destination address in the packet. The second interface transfers the packet to another protocol analyzer.
In variations of the invention, the control system may transfer the packet to the second interface if the destination address is on an address list. The address list may be compiled from source addresses in other packets received by the second interface.
The control system may also transfer the packet to the second interface if the destination address is within an address range.